zeroz6969z

i have an 87 formula and im putting in a 400hp motor and built tranny with a 2200 stall converter. i have the stock 10 bolt in the rearend what would suggest i get as a rearend. i already have wheel adapters for newer camaro ss rims im not sure if a newer camaro or ta rearend would fit or if something else would work. i prefer not to change anything if i can.

thank you
steve

Rice Killer87

u can build the 10 bolt thats in there to hold up. u can get a bigger spline axle,an eaton or auburn posi unit and a good set of gears (if u dont have them already) and should be good 2 go.

lordmetalz28

dont even worry about your axels they hold up to much more then you think. just weld the axel tubes. call randys ring and pinion for excellent prices

Aklaim

Ive seen numerous axels snap in half, so to say that they will be ok is a bit misleading. Can they survive that much power? Definetly. Will they if you are laying into them every chance you get? Hell no. I'm still not sure why you guys weld the axle tubes, but whatever....its your car. The seams on the rear housing arent the problem, its the gear size. Its too small and flexes under high load, and yes will shatter if too much power is applied all at once. If it flexes the diff moves and BOOM.....Welded axle tunes will not prevent the gear from flexing......

aklim

I have seen properly supported rear ends support 500 HP when the tranny is an A4. Mine lasted for a few years with the 383 in front of it.

With an A4, you are not dropping the clutch at 5000+ rpm

WhiteKid

Your 10 bolt will def hold up to 400rwhp if its built properly. If you wanna go much higher then 400hp or your planning on racing on an every day basis you should definetally invest in a 12 bolt or 9 inch rear end. But if your using it as a daily driver why waste the $1000+ I have the 10 bolt with 2.73's and im gonna have it rebuilt this summer with 3.73's.

Marc 85Z28

If you already have th 4th gen wheels I'd suggest that you go with either a 12 bolt or aftermarket 9" rear designed for the 4th gen cars. That way you could offset some of the cost by selling your current 10 bolt, AND the adapters too.

Your stock 10 bolt can be built to handle 400HP on street tires, but not for very long. Some last, some don't. Kind of a hit or miss cross your fingers thing Do a search for the 10 bolt buildup.

Aklaim: Richmond gear claims the #1 failure in the 7.5" 10 bolt is cause by housing flex.

lordmetalz28

housing flex/ bearing main cap flex. there for you get the aluminum cover which supports the rear end and holds the bearing caps in place. and running a 305 your axels wont snap for a while for a long while. almost forever

lordmetalz28

aklaim is also the guy who would rather save air thats already screwed up instead of adding some horse power. dont listen to him

Aklaim

I'm not sure what your problem is but you need to relax. Also, I highly doubt hes pumping out 400hp out of a 305....Eevn with a girlde its still VERY possible to blow the rear AND snap the axles...

lordmetalz28

im joking bro dont get your ******* in an uproar. i highly doubt a 250hp 305 could snap those axels. it could happen but unlikley is all im saying.

Marc 85Z28

Who said anything about a 305? The original poster sure didn't. It's safe to assume it will be at least 350ci.

And yes, even with welded tubes, a girdle with cap supports, and aftermarket internals its still possible to blow the rear or snap the axles. Welding the tubes and adding the support doesn't eliminate ALL flex. And I HIGHLY doubt the axles will go before anything else, especially the spider gears!

Zepher

If you prefer not to change anything, then I guess just leave the rear as is and hope for the best.

If you already have wheel spacers, you can always get a 12bolt with the 4th gen offset and then sell the spacers.
Also, why go with such a small stall?

Aklaim

He said 305...

lordmetalz28

im only concerened about myyyyyy 305 thats why i said it. well see what happens to my rear in a few years then ill tell you